This invention relates to a toner for developing an electrostatic latent image, a production method of the toner for developing an electrostatic latent image and an image forming method using the toner for developing an electrostatic latent.
At present, an electrostatic latent image developing method is widely applied in the image forming process of a copy machine, a printer and a facsimile machine because a high quality image can be formed at a high speed by such the method, the method can correspond to an analogue image forming process, a color image forming process and a digital image forming process and the method has a high accomplishment and a high stability and a durability of the performance.
Accordingly, a demand to the method to raise the image quality is strong and a further improvement in the image quality is required. As the countermeasure to such the requirement, it has been investigated as the most effective way that the particle size of the toner for developing electrostatic latent image, hereinafter simply referred to the toner, is made small and the particle size distribution width of the toner particles is made narrow.
The toner produced by a polymerization is preferable to form a high quality image since the toner having a small particle size and a narrow size distribution can be easily obtained by the polymerization method. However, a releasing agent is not exposed at the surface of the toner particle produced by the polymerization method. The toner produced by such the method has problems that the fixing ability by a thermal fixation is low and a toner off-set is occurred to the surface of the heating member of the fixing device.
The object of the invention is to provide a toner with a high fixing ability and without occurring of the off-set, by which an image can be formed stably for a long duration, a production method of such the toner and an image forming method using the toner. The other object of the invetion is to provide a toner with minimized filming problem on a photoreceptor and deformation of image blurring. The other object of the invention is to provide a toner having excellent fixing characteristics and giving high image quality after long storage.
The invention and an embodiment thereof are described below.
1. A toner for developing an electrostatic latent image comprising a resin, a colorant and a releasing agent, the releasing agent comprising a mixture of a plurality of compounds represented by formula (1)
R1xe2x80x94(OCOxe2x80x94R2)nxe2x80x83xe2x80x83(1) 
wherein n represents an integer of 1 to 8 carbon atoms which may has a substituent, R1 is a hydrocarbon group having from 1 to 40, R2 is a hydrocarbon group having from 8 to 40 carbon atoms which may has a substituent, wherein the mixture is composed of
(a) from 80 to 90 weight % of the compound represented by Formula (1), R2 of which has N carbon atoms,
from 3.0 to 10.0 weight % of the compound represented by Formula (1), R2 of which has Nxe2x88x922 carbon atoms,
from 1.0 to 5.0 weight % of the compound represented by Formula (1), R2 of which has Nxe2x88x924 carbon atoms,
from 0.1 to 2.0 weight % of the compound represented by Formula (1), R2 of which has Nxe2x88x926 carbon atoms, and
from 0.5 to 3.0 weight % of the compound represented by Formula (1), R2 of which has N+2 carbon atoms, or
(b) from 80 to 90 weight % of the compound represented by Formula (1), R1 of which has N carbon atoms,
from 3.0 to 10.0 weight % of the compound represented by Formula (1), R1 of which has Nxe2x88x922 carbon atoms,
from 1.0 to 5.0 weight % of the compound represented by Formula (1), R1 of which has Nxe2x88x924 carbon atoms,
from 0.1 to 2.0 weight % of the compound represented by Formula (1), R1 of which has Nxe2x88x926 carbon atoms, and
from 0.5 to 3.0 weight % of the compound represented by Formula (1), R1 of which has N+2 carbon atoms.
In the toner mentioned above, (a) is preferable. Preferable N is from 8 to 36, and more preferably from 8 to 30.
When n is 1, R1 is a hydrocarbon group preferably having carbon atoms of from 13 to 31.
When n is from 2 to 8, R1 is a hydrocarbon group preferably having carbon atoms of from 2 to 15.
Preferably n is 3 or 4, and more preferably 4.
The toner particle is composed of preferably fused resinous particles containing the releasing agent.
The toner is preferably obtained by fusing resinous particles containing the releasing agent in a water based medium.
In the other embodiment, the toner is obtained by fusing, in water based medium, resinous particles containing the releasing agent and colorant.
In the further other embodiment, the toner is obtained by suspension polymerization of monomer composition containing monomer, the releasing agent and colorant in water based medium.